Continuous feed vibratory finishing method with discharge rate controlled by operation of tub discharge closure

ABSTRACT

A vibratory finishing machine including a supporting frame, a processing tub, and a tub vibrating mechanism interposed between the frame and the tub. A continuous feed finishing operation is provided by charging the workpieces and media into one end of the tub and discharging them through an opening in the opposite end of the tub. The bottom of the discharge opening extends substantially level with the bottom of the tub thereby providing no obstruction which will cause liquids or other materials to be retained for excessive times within the tub. A power-operated closure is mounted on the tub for selectively closing and opening the discharge opening. The closure is movable toward and away from the discharge opening along a path generally perpendicular to the opening to control the discharge of materials from the tub, thereby controlling the retention time of the materials in the tub.

United States Patent [191 Rampe CONTINUOUS FEED VIBRATORY FINISHING METHOD WITH DISCHARGE RATE CONTROLLED BY OPERATION OF TUB DISCHARGE CLOSURE [75] Inventor: John F. Rampe, Mayfield Heights,

Ohio

[73] Assignee: Rampe Research, Cleveland, Ohio [22] Filed: Feb. 14, 1974 [21] App]. No.: 442,442

Related US. Application Data [60] Division of Ser. No. 270,700, July 11, 1972, Pat. No. 3,831,322, which is a continuation-in-part of Ser. No. 8,815, Feb. 5, 1970, Pat. No. 3,685,213.

3,694,968 10/1972 lsaacson ..51/l63 Aug. 12, 1975 Primary Examiner-Harold D. Whitehead Attorney, Agent, or Firm-Watts, Hoffmann, Fisher & Heinke Co.

[5 7] ABSTRACT A vibratory finishing machine including a supporting frame, a processing tub, and a tub vibrating mechanism interposed between the frame and the tub. A continuous feed finishing operation is provided by charging the workpieces and media into one end of the tub and discharging them through an opening in the opposite end of the tub. The bottom of the discharge opening extends substantially level with the bottom of the tub thereby providing no obstruction which will cause liquids or other materials to be retained for excessive times within the tub. A poweroperated closure is mounted on the tub for selectively closing and opening the discharge opening. The closure is movable toward and away from the discharge opening along a path generally perpendicular to the opening to control the discharge of materials from the tub, thereby controlling the retention time of the materials in the tub.

7 Claims, 6 Drawing Figures SHEET PATENTED AUG 1 2 i975 CONTINUOUS FEED VIBRATORY FINISHING METHOD WITH DISCHARGE RATE CONTROLLED BY OPERATION OF TUB DISCHARGE CLOSURE CROSS REFERENCE TO RELATED PATENTS AND APPLICATION This is a division of application Ser. No. 270,700 filed July 11, 1972, now issued at U.S. Pat. No. 3,831,322,

which is, in turn, a continuation-in-part of application BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to abrasive finishing machines and more particularly to a vibratory finishing machine of the continuous feed type having a discharge system for controlling the retention time of workpieces within the tub of the machine.

2. Prior Art Vibratory finishing machines adapted to smooth and finish the surfaces of workpieces by such operations as deburring, burnishing, descaling, and cleaning are well known. Such machines commonly employ a processing tub adapted to receive a quantity of workpieces and abrasive finishing media. The tub is then vibrated so as to impart a finishing action to the workpieces.

As brought out in the referenced patents, the abrasive media can conveniently be separated from the workpieces after the media and workpieces are discharged from the tub. After separation, the finishing media may then be returned to the tub of the finishing machine for re-use. The finishing liquid is usually drained off during separation of the media and workpieces. The finished workpieces are subsequently collected and conveyed to a separate unit or group of units for washing, drying, inspection and packaging.

Various proposed continuous feed vibratory finishing machines are also known. Such proposed machines provide the processing tub with spaced charging and discharging devices whereby media and workpieces enter one end of the tub and are subjected to a finishing action as they progress through the tub for discharge at the opposite end.

One problem with prior proposals for continuous feed vibratory finishing machines is that the time during which workpieces are retained in the tub is not readily controllable. Workpieces of a relatively soft metal, or workpieces needing only minimal deburring, etc., require only a short retention time. Workpieces of harder metal which have many large burrs to be removed, will require longer retention times. Hence, where the retention time requirements differ from that provided by prior art continuous feed finishing machines, it has previously been necessary to operate the finishing machine on a batch process basis where the retention time can be carefully controlled.

One problem which has been occasioned with the apparatus described in the referenced Continuous Feed Patent, is that the weir structure forming the bottom lip of the discharge opening tends to trap and cause the undesirable buildup of some materials, particularly liquids, within the finishing machine tub. Periodically the machine must be shut down and undesirable materials cleaned out of the tub.

SUMMARY OF THE INVENTION The present invention overcomes the foregoing drawbacks of the prior art finishing machines and provides a finishing machine with a discharge system for controlling the retention time of workpieces in the tub of the machine.

The finishing machine of the present invention may be operated on a batch basis if so desired but is designed primarily for continuous operation according to a pre-arranged time schedule. Pursuant thereto, a discharge system is provided including a closurecontrolled discharge opening the bottom of which is not substantially higher than the bottom of the finishing machine tub whereby no obstruction is provided which will cause the accumulation of materials in the tub.

It has been found that the retention time of workpieces in the tub can adequately be controlled without a weir type discharge opening by carefully controlling the operation of the discharge closure. One of the advantages of the invention resides in the flexibility of the closure operating cycle, which can be adjusted by the operator from time to time to lengthen or shorten the retention time of materials within the tub. The discharge closure can be opened and closed by a timing control device preset to selected intervals of operation.

Once the closure operating cycle has been decided upon, the operator adjusts the timing mechanism to provide the pre-determined retention period--typically ten seconds-- for processing the workpieces constituting part of the contents of the tub. This is normally followed by a release period--typically 5 seconds--for partial discharge of materials from the tub. This cycle of closure operation is continually repeated and establishes an effective rate of discharge of materials from the tub which determines the retention time of workpieces in the tub. In some cases, the nature of the workpieces may call for longer or shorter processing times than those mentioned above; in such instances, the operator can readily re-set the timing mechanism to provide correspondingly longer or shorter retention periods preceding the release periods.

In the operation of the machine, the charging apparatus supplies the tub as required with suitable abrasive processing media. An aqueous finishing liquid is usually introduced concurrently therewith to facilitate finishing of the workpieces. The workpieces themselves are added by the operator. For all practical purposes, the operation of the charging apparatus is, in effect, keyed to that of the discharge system and simply returns the abrasive media which has been discharged from the tub back into the tub.

In accordance with one aspect of the present invention, the discharge system includes a discharge structure projecting from one end of the tub and defining a discharge opening which is inclined slightly upwardly to correspond with the approximate angle of inclination of the leading surface of materials as they discharge from the tub. A door structure is provided which is movable into and out of registry with the discharge opening along a path which is generally perpendicular to the discharge opening. The door is guided by a pair of guide rods disposed on opposite sides thereof. A pneumatically operated bellows is provided to effect closure movements of the doors structure. A pair of compression coil springs carried on the guide rod bias the door to the open position and are operative to collapse the bellows when the bellows is vented to atmosphere by a timer controlled valve.

Accordingly, it is the principal object of. the present invention to provide a vibratory finishing method including an improved discharge process for controlling the retention time of workpieces in the processing tub.

Other objects and fuller understanding of the invention may be had by referring to the following description and claims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an orbital finishing machine within the perview of the present invention;

FIG. 2 is a top plan of the machine on a somewhat larger scale;

FIG. 3 is a side elevational view showing on a still larger scale the discharge closure assembly at the end of the tub seen at the right in FIGS. 1 and 2, with the discharge closure in open position.

FIG. 4 is a corresponding vertical section as seen from the plane indicated by the line 44 in FIG. 2, with the discharge closure in closed position;

FIG. 5 is a view on the same scale as FIG. 3 as seen from the plane indicated by the line 55 in FIG. 3; and FIG. 6 is a view on the same scale as FIG. 3 as seen from the plane indicated by the line 66 in FIG. 3.

DESCRIPTION OF PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, a finishing machine 10 constructed in accordance with the present invention includes a platform 11 which supports a motor 12. A chain belt drive system 13 couples the motor 12 to a vibration inducing system (not shown) of the type described in the referenced Orbital Patent for vibrating a tub 20. A guard 14 shields the chain belt drive system. A shroud 15 encloses much of the understructure of the machine 10.

Adjoining the shroud 15 is a console 16 which mounts a control box 17. A conventional timing mechanism l8 programmable by an operator in a manner which will be described is housed within the control box 17.

The tub 20 is generally cylindrical in shape and is supported from beneath as described in the Orbital Patent. A wide, longitudinally extending opening 21 is defined by mutually diverging wings 22 formed on the tub 20. A plurality of cross heads 23 bridge the space separating the wings 22.

A generally square end plate 24 is aligned with the tub 20 at its charging end, the left end as seen in FIG. 2. A central circular opening of substantially the same diameter as the tub 20 is formed through the end plate 24 to admit finishing media to the tub 20. A hopper 25 is attached to the end plate 24 for feeding plastic or stone finishing media through the opening in the end plate 24 and into the tub 20. An elongated top opening 26 is formed in the hopper. The top opening 26 receives finishing media dropped from the upper end of a bucket conveyor 27.

The conveyor 27 is mounted in a framework 28 supported by suitable uprights 29. A motor 30 supplied power to the conveyor 27 near its upper end. The lower end of the conveyor 27 is supported within a housing 31. The conveyor 27 provides a means of returning media discharged from the machine 10 back into the tub 20 for re-use.

A square end plate 34 is mounted on the right end of the tub 20, as viewed in FIG. 2. The end plate 34 has a central aperture which is in alignment with the bottom of the tub such that finishing media, finished parts, abrasive chips, liquids, and such other materials as may be present in the tub 20 can be discharged without obstruction. A discharge structure 38 communicates with the aperture in the plate 34 and defines a discharge opening 39. A power operated closure system, indicated generally by the numeral 40 is provided to selectively open and close the end of the discharge opening 39.

Referring to FIGS. 3 and 4, the end plate 34 is secured to the end of the tub structure 20 by fasteners 35. A resilient sheet 36 of tub lining material is interposed between the tub structure 20 and the plate 34. The end plate 34 and the tub lining sheet 36 have aligned apertures as shown at 37 in FIG. 4.

The discharge structure 38 is welded to the plate 34 and communicates with the apertures 37 to provide a smooth conduit for the discharge of materials from the tub 20. The bottom of this discharge conduit is level with the bottom of the tub 20 so that it does not obstruct the discharge of materials from the tub 20.

The outer end 39 of the discharge structure 38 extends in a plane inclined at an angle of approximately 30 from the vertical and has exit surfaces defining an inclined discharge opening 39. By inclining the plane of the discharge opening 39 in this manner, the discharge opening tends to lie in nearly the same plane as the leading surface of materials discharging from the tub structure 20. A power operated closure 40 including a bellows 45 operates to selectively open and close the discharge opening 39.

The closure system 40 includes a heavy metal frame welded to the end plate 34. The supporting frame includes a pair of V-shaped side plates 41, 42 welded to the end plate 34, and a cross-member 43 welded to the side plates 41, 42. A pair of fasteners 44 extend through apertures formed in the crossmember 43 and mount a pneumatically actuated bellows 45.

The bellows 45 preferably comprises such a bellows as is sold by Firestone Tire and Rubber Company of Akron, Ohio under the designation Airide 26B. The bellows 45 is expansible during inflation from the deflated configuration shown in FIG. 3 to the inflated configuration shown in FIG. 4. A conduit 46 extends through an aperture in the cross-member 43 for supplying air to and exhausting air from the bellows 45.

A movably mounted closure assembly 47 is secured by fasteners 48 to the other end of the bellows 45, as is best seen in FIGS. 4 and 6. The closure assembly 47 includes a resilient closure lining sheet 49 adhered to a channel shaped mounting plate 50. The lining sheet 49 facilitates the formation of a liquid tight seal when the closure 40 is closed against the discharge structure 38.

A pair of bushings 51, 52 are mounted in apertures formed through the plate 50. The bushings 51, 52 slidably receive a pair of guide rods 53, 54. The inner ends site sides of the path of travel at the closure assembly 47 to guide the movement of the closure assembly 47. Movement of the closure assembly toward and into contact with the discharge structure 38 is effected by inflating the bellows 45. Movement of the closure assembly to the open position of FIG. 3 is effected by a pair of compression coil springs 57,58 mounted on the guide rods 53, 54. The springs 57, 58 engage the bosses 55 at one end and engage the bushings 51, 52 at the other end. When the bellows 45 is inflated with sufficient pressure, the biasing action of the springs 57, 58 is overcome and the closure assembly 47 is caused to move toward the discharge structure 38. When the pressure within the bellows 45 is released, the springs 57, 58 move the closure assembly 47 to the open position, collapsing the bellows and exhausting air through the conduit 46.

The timing mechanism 18 is arranged in conventional fashion to operate an air valve 60. In one selectable position, the valve 60 serves to admit compressed air from a conduit 61 to the conduit 46 for inflating the bellows 45. In another selectable position, the valve 60 serves to vent the conduit 46 to atmosphere permitting the collapse of the bellows 45 under the influence of the springs 57, 58. The timing mechanism 18 is preferably programmable to cyclically operate the valve 60 to open and close the closure 40 for selected intervals of time.

Materials discharging throughthe opening 39, drop into a substantially horizontally disposed trough 65. The trough 65 is provided just above its bottom with an inclined fine mesh screen 66. The openings in the screen 66 are small enough to prevent the passage at workpieces and finishing media therethrough while allowing the entrained finishing liguid to separate and drip through to the bottom of the trough 65. The finishing liquid may be recirculated, if desired, or simply allowed to drain into a collected vessel or sewer. In the meantime, the workpieces and finishing media are urged toward the far end of the screen 66 by gravity and/or forces imposed on them by subsequently discharging tub contents.

At the remote end of the trough, the screen 66 is equipped with a wide-mesh insert 67 that allows the media, but not the workpieces, to drop through the in sert 67 and into the lower end of conveyor 27. The conveyor 27 carries the finishing media toward its upper end for return to tub through hopper 26. The workpieces are precluded by the widemesh insert 67 from dropping through this portion of the screen, and move onto an inclined run-off tray 68. The workp'ieces then fall by gravity into a waiting tote box or other receptacle.

In normal operation, the workpieces, together with the desired type or types of media, are vibrated in the tub 20, with the closure 40 in the closed position, for a selected retention period. The closure 40 is then opened permitting the tub contents, consisting of the workpieces media and fluid, etc., spill out through the opening 39 into trough 65 an onto screen 66. After a suitable discharge interval, the timing mechanism 18 operates to move the closure 40 to its closed position.

The retention time of the workpieces in tub 20 can be increased or decreased by adjusting the timing mechanism 18 in accordance with the type of materials being finished.

Although the invention has been described in its preferred form with a certain degree of particularlity, it is understood that the present disclosure of the preferred form has been made only by way of example and numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

What is claimed is:

1. A continuous feed process for finishing workpieces in the tub of a vvibratory finishing having a closure for selectively opening and closing a tub discharge opening, comprising the steps of:

a. feeding workpieces and media into the tub at a location spaced from the discharge opening;

b. vibrating the tub to impart a motion to the workpieces and media to preform a finishing operation on the workpieces and to move the workpieces and media from said location toward the discharge opening; and,

c. repetitively cyclically opening and closing the closure during the period while each workpiece is retained in the tub to control the rate at which workpieces and media discharge through the opening to control the retention time of workpieces within the tub.

2. A continuous feed process of finishing workpieces in the tub of a vibratory finishing machine having a closure for selectively opening and closing a tub discharge opening, comprising the steps of:

a. feeding workpieces and media into the tub at a location spaced from said discharge opening;

b. vibrating the tub to impart a motion to the workpieces and media to preform a finishing operation on the workpieces and to move the workpieces and media from said location toward the discharge opening; and

c. repetitively cyclically moving the closure along a path substantially perpendicular to the opening to repetitively bring the closure into and out of registry with the discharge opening for selected intervals of time during the period while each workpiece is retained in the tub to control the retention time of materials within the tub.

3. The process of claim 2 additionally including the step of providing a timing control to automatically control the time intervals between opening and closing of the closure.

4. A continuous process for finishing workpieces in the tub of a vibratory finishing machine having a tub discharge opening and a movable member for selectively permitting and obstructing the passage of workpieces and finishing media through the discharge opening, comprising the steps of:

a. continuously vibrating the tub to impart a motion to workpieces and finishing media in the tub and to move the workpieces and finishing media continuously through the tub toward the discharge opening from a charging location spaced from the discharge opening;

b. during the movement of the workpieces through the tub, continuously cyclically moving the member a plurality of times between positions where the passage of workpieces and finishing media through the discharge opening is permitted and obstructed; and,

c. controlling the average time during which workpieces are retained in the tub by controlling the cyclical movement of the member to limit the rate at which workpieces and media are permitted to pass through said discharge opening.

5. The process of claim 4 additionally including the step of feeding workpieces and media into the tub at said charging location at a substantially continuous rate which corresponds to the rate at which workpieces and media pass through the discharge opening.

6. In a continuous feed finishing process of the type where workpieces and finishing media are caused to process during finishing through a finishing machine tub toward a tub discharge opening and are subsequently discharged from the tub through the opening,

the improvement of controlling the time during which workpieces are retained in the tub by the step of repetitively cyclically moving a member between positions where the passage of workpieces through the opening is selectively pennitted and restricted to establish a substantially constant effective discharge rate which causes workpieces to be retained in the tub for substantially the desired period of time.

7. The process of claim 6 wherein said member is a closure movable between open and closed positions where the discharge opening is opened and closed, and the step of cyclically moving said member is carried out by moving said closure between said open and closed positions. 

1. A continuous feed process for finishing workpieces in the tub of a vibratory finishing having a closure for selectively opening and closing a tub discharge opening, comprising the steps of: a. feeding workpieces and media into the tub at a location spaced from the discharge opening; b. vibrating the tub to impart a motion to the workpieces and media to preform a finishing operation on the workpieces and to move the workpieces and media from said location toward the discharge opening; and, c. repetitively cyclically opening and closing the closure during the period while each workpiece is retained in the tub to control the rate at which workpieces and media discharge through the opening to control the retention time of workpieces within the tub.
 2. A continuous feed process of finishing workpieces in the tub of a vibratory finishing machine having a closure for selectively opening and closing a tub discharge opening, comprising the steps of: a. feeding workpieces and media into the tub at a location spaced from said discharge opening; b. vibrating the tub to impart a motion to the workpieces and media to preform a finishing operation on the workpieces and to move the workpieces and media from said location toward the dIscharge opening; and c. repetitively cyclically moving the closure along a path substantially perpendicular to the opening to repetitively bring the closure into and out of registry with the discharge opening for selected intervals of time during the period while each workpiece is retained in the tub to control the retention time of materials within the tub.
 3. The process of claim 2 additionally including the step of providing a timing control to automatically control the time intervals between opening and closing of the closure.
 4. A continuous process for finishing workpieces in the tub of a vibratory finishing machine having a tub discharge opening and a movable member for selectively permitting and obstructing the passage of workpieces and finishing media through the discharge opening, comprising the steps of: a. continuously vibrating the tub to impart a motion to workpieces and finishing media in the tub and to move the workpieces and finishing media continuously through the tub toward the discharge opening from a charging location spaced from the discharge opening; b. during the movement of the workpieces through the tub, continuously cyclically moving the member a plurality of times between positions where the passage of workpieces and finishing media through the discharge opening is permitted and obstructed; and, c. controlling the average time during which workpieces are retained in the tub by controlling the cyclical movement of the member to limit the rate at which workpieces and media are permitted to pass through said discharge opening.
 5. The process of claim 4 additionally including the step of feeding workpieces and media into the tub at said charging location at a substantially continuous rate which corresponds to the rate at which workpieces and media pass through the discharge opening.
 6. In a continuous feed finishing process of the type where workpieces and finishing media are caused to process during finishing through a finishing machine tub toward a tub discharge opening and are subsequently discharged from the tub through the opening, the improvement of controlling the time during which workpieces are retained in the tub by the step of repetitively cyclically moving a member between positions where the passage of workpieces through the opening is selectively permitted and restricted to establish a substantially constant effective discharge rate which causes workpieces to be retained in the tub for substantially the desired period of time.
 7. The process of claim 6 wherein said member is a closure movable between open and closed positions where the discharge opening is opened and closed, and the step of cyclically moving said member is carried out by moving said closure between said open and closed positions. 